I generally only bump into two types of people: DF fanatics (players), or people who know the depth of DF and agonize that they can't get into it
I hang around mostly dwarfly places, though, so its no real surprise
Anyway, the real trick will be balancing DF feature additions against the dreaded (and already very real) "FPS death", in the future.. And a nice interface and graphics don't amount to nearly as much when a lot of the content is missing (see Gnomoria, amazing UI/graphics, elementary-school-level depth compared to DF)..
Overall, I don't worry much about DF, the fanbase, or the future of the game.. To be toppled, another developer (or team) would have to work for years just to match DF in content, which would be especially difficult with Toady creating new content all throughout :>
And then DF has so many hooks to snag people (FOR LIFE) with: the detailed/hilarious combat, the worldgen, adv mode, the intense list of creatures, the digging, the hoarding, the modding, the random-gen beasts and artifacts, the storytelling, the science, the interactivity, and twenty more
Any one of those features alone is enough to inspire people to overcome the UI (which ends up becoming totally usable eventually) and the ascii (plenty of nice tilesets to choose from).. Honestly, on UI, I'm more comfortable with the DF UI versus Gnomoria
Most likely because I spent a couple years getting comfortable with DF, and only spent about two hours with Gnomoria (logging its short-comings when compared to DF)..
I honestly think Toady has made himself a pretty good tombstone here
IF we get off this planet before it gets vaporized, I doubt they'll take Tarn's corpse/tombstone/ashes with them, but I imagine DF will leave with us, if it ever happens :> I see DF still being played a couple hundred years from now, unless something superior shows up between now and then (and the overall capitalist-based approach to game development nearly guarantees that it'll remain unique..)